The death toll from a gas explosion at a coal mine in China has risen to 37, with another 10 people trapped, authorities said on Aug. 31, in one of the country’s worst mining accidents of the last year.

There were 154 workers underground when the blast hit the Xiaojiawan mine in southwest China’s Sichuan province in the morning on Aug. 29.

Rescue workers have struggled to gain access to the area where the miners are trapped, hampered by temperatures as high as 90 degrees Celsius (190 degrees Fahrenheit) and high levels of poisonous carbon monoxide gas.

Emergency crews have pulled 34 bodies from the mine, while another three workers were rescued but later died of their injuries, the official Xinhua news agency said. Another 17 were being treated for serious injuries.Worst coal mine accident in China since November

It is believed to be the worst coal mining accident to hit China since an explosion last November in a mine in southwestern Yunnan province killed 43 people.

The China Daily, quoting the government’s head of mine safety, said the roof of the mine was also in danger of collapsing, further hampering rescue efforts.